Twenty five years ago Adler Barbour to increased sales added a small water cooled condenser and a larger BTU brush type motorcompressor, labeling it as the Super Cold Machine. Several years later the larger brush type compressor was replaced with the same smaller standard Cold machine’s Danfoss brushless compressor. In warmer climates where the watercooling option was to improve performance the added amperage to operate water pump off set the savings projected for a Super Cold Machine. I believe Isotherm was the first company using water cooled only on small Danfoss BD compressor. The Isotherm unit was short lived I believe do to short water pump life. Isotherm water cooled units did not supplement compressor cooling with fan air but did circle compressor on three sides with 11 ft of water and condenser cooling coils. Once the creative water cooling was a great marketing idea other companies and job shops came out with their version of water cooling Danfoss BD compressors. At first small ice box refrigeration conversion companies designed units that circulated water through condenser with a 12 volt pump and eliminated the air cooled fan and its condenser. Water circulating pumps performed poorly when boats were in motion. Any 12 volt pump motor with brushes that is expected to run fifty present of the time will be short lived. I once sold four of these pumps to a boater planning an extended cruise. Some companies used positive displacement pumps that were an improvement when boat was in motion but these pumps also had a short life span. Magnetic circulating small pumps are now available with extended life. Still the main problem with circulating water condenser is maintaining water flow. Circulating water cooling is not a refrigeration system that can be left unattended for more than a day. When system with only a pumped circulating water condensers unit were not as dependable as air cooled condensers manufactures began adding a second fan cooled condenser. With both types of cooling medium condensers allowed boatcaptain to select either or both condensers. One problem with the dual condenser systems is the air cooled condenser is not always designed to be installed where air is ducted in from one area and warm air exhausted to another area.

The next generation of water cooled small ice box conversion refrigeration units after experiences with pumped water condenser problems manufacturers tried hull mounted submerged condensers. These hull mounted units eliminate the cooling fan saving from 3 to 6 amp-hrs per day. Refrigeration companies pushing the believed improved performance from water cooled units actually got their major marketing boost from the new variable speed Danfoss compressors and not water cooling. The problem without a condenser and compressor cooling fan exposes compressor to excessive temperatures in warm seawater. The loss of an air cooling fan has an affect on service life of compressor and also service life of the electric control module. Hull mounted condensers whether keel coolers or through hull coils suffer from two of the pumped water unit’s major troubles, loss of metal material if zinc protectors are not maintained and both of these hull condensers need frequent cleaning to maintain their efficiency.

Yes, water cooled refrigeration systems larger than 800 Btu per hour do normally require water cooling with all the unfriendly problems that come with water cooling.. Considering all the risks involved with water cooling a refrigeration system smaller than 1/6 horse power the question is, what motivated the interest and belief that an expensive water cooled system offered an improved benefit to the average boater. Not every boater operates their boat in water temperatures of 65 to 75 degrees F where water cooling could be more efficient than air cooling. Manufacturers when it comes to product risk and reward will sell what ever the buyer believes is an advanced product. One misinformed statement you hear frequently is water cooling is a better heat conductor in a refrigerator than air. The problem here is none of these small water cooled systems sold today control the temperature passing through condenser to control liquid refrigerant pressure as well as ambient air temperature inside boat.

Yesterday I answered an email from a boater wanting to install two 12/24 volt refrigeration systems with BD50 compressors in a large aluminum hull boat. Having seen and experienced the damage cased by low voltage discharge through condenser water I would never again recommend seawater refrigeration cooling on an aluminum boat without adequate electrical isolation and regular sacrificial zinc maintenance. It is one thing to sell a water cooled system that destroys itself but I do not ever again want to be involved with a design that causes a boat hull skin to be reduced to ½ its original thickness in one year because of low voltage discharge.

The Following questions will help test your beliefs on small pleasure boat marine refrigeration.

1. Air cooled refrigeration units of less than 800 Btu per hour are more efficient than water cooled when seawater temperature is above 80 degree F. or below 65 degrees? True or False

2. Danfoss recommends and approves the BD model compressor to be water cooled in application engineering data sheets? True or False

3. Air cooled refrigeration is five times less expensive to maintain than water cooling? True or false

I had an Adler Barber on one boat. The boat had a small 2 cu ft refridge in the middle of a huge salon table. I never used the big refrigerator in the galley. In the Caribe I found no practical difference if I ran the AB with the water cooling pump or just the fan. (it had both, obviously) Meaning engine run time to replenish batteries was the same and the food temp appeared to be the same. Eventually I just disconnected the pump.

__________________"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard

Twenty five years ago Adler Barbour to increased sales added a small water cooled condenser and a larger BTU brush type motor compressor, labeling it as the Super Cold Machine. Several years later the larger brush type compressor was replaced with the same smaller standard Cold machine’s Danfoss brushless compressor. In warmer climates where the water cooling option was to improve performance the added amperage to operate water pump off set the savings projected for a Super Cold Machine. Pity they didn't use a magnetic drive centrifugal pump. Quiet and uses less than one third of an amp when running. I believe Isotherm was the first company using water cooled only on small Danfoss BD compressor.Really? The Isotherm unit was short lived I believe do to short water pump life. Isotherm water cooled units did not supplement compressor cooling with fan air but did circle compressor on three sides with 11 ft of water and condenser cooling coils. Once the creative water cooling was a great marketing idea other companies and job shops came out with their version of water cooling Danfoss BD compressors. At first small ice box refrigeration conversion companies designed units that circulated water through condenser with a 12 volt pump and eliminated the air cooled fan << Yes a big mistake not cooling the electronic driver. and its condenser. Water circulating pumps performed poorly when boats were in motion. Any 12 volt pump motor with brushes that is expected to run fifty present of the time will be short lived. Absolutely but who in their right mind would use a pump with brushes! They went out with the horse and cart!
I once sold four of these pumps to a boater planning an extended cruise. Some companies used positive displacement pumps that were an improvement when boat was in motion but these pumps also had a short life span. Magnetic circulating small pumps are now available with extended life. Still the main problem with circulating water condenser is maintaining water flow. Circulating water cooling is not a refrigeration system that can be left unattended for more than a day. Really! This comment is very general and does not relate to all water cooled systems. Certainly not the OzefridgeWhen system with only a pumped circulating water condensers unit were not as dependable as air cooled condensers manufactures began adding a second fan cooled condenser. With both types of cooling medium condensers allowed boat captain to select either or both condensers. The best solution is a combined air &
water cooled condenser specially like the Ozefridge condenser where the water and refrigerant galleries are only in contact via fins therefore NO possibility of contaminationOne problem with the dual condenser systems is the air cooled condenser is not always designed to be installed where air is ducted in from one area and warm air exhausted to another area.Absolutely, that is why our system is air and water cooled with the water cooling only involved if the condenser refrigerant reaches 43C.
In other words if the air cooling is not doing it's job due to say being in the engine room or the ambient is high, the watercooling kicks in and assists. Simple!

The next generation of water cooled small ice box conversion refrigeration units after experiences with pumped water condenser problems manufacturers tried hull mounted submerged condensers. These hull mounted units eliminate the cooling fan saving from 3 to 6 amp-hrs per day. Refrigeration companies pushing the believed improved performance from water cooled units actually got their major marketing boost from the new variable speed Danfoss compressors and not water cooling. The problem without a condenser and compressor cooling fan exposes compressor to excessive temperatures in warm seawater. The loss of an air cooling fan has an affect on service life of compressor and also service life of the electric control module. Hull mounted condensers whether keel coolers or through hull coils suffer from two of the pumped water unit’s major troubles, loss of metal material if zinc protectors are not maintained and both of these hull condensers need frequent cleaning to maintain their efficiency. Here is where we generally agree. We believe that raw water should NEVER be used in any way where 12 /24VDC refrigeration is involved. The damage to compressors is not caused by water cooling as such but more from poorly controlled and plainly crazy methods of disipating condenser heat. In fact a properly engineered air/ water cooled system that maintains a controlled condenser temperature, will cause the compressor less stress than an air only system, unless always used in a cooler /moderate environment where water cooling is totally unnecessary .

Yes, water cooled refrigeration systems larger than 800 Btu per hour do normally require water cooling with all the unfriendly problems that come with water cooling.. Considering all the risks involved with water cooling a refrigeration system smaller than 1/6 horse power the question is, what motivated the interest and belief that an expensive water cooled system offered an improved benefit to the average boater. Not every boater operates their boat in water temperatures of 65 to 75 degrees F where water cooling could be more efficient than air cooling. Manufacturers when it comes to product risk and reward will sell what ever the buyer believes is an advanced product. One misinformed statement you hear frequently is water cooling is a better heat conductor in a refrigerator than air.'REALLY'! Water cooling IS a FAR better conductor of heat. Water conducts heat nearly 25 times faster than air. A good test is to start with two hot cans of beer. Put one in 2C icy water and the other in a 2C fridge and I know which one gets drunk fist! (unless you're British!) The problem here is none of these small water cooled systems sold today control the temperature passing through condenser to control liquid refrigerant pressure as well as ambient air temperature inside boat.Correct, most don't but the Ozefridge certainly does.

Yesterday I answered an email from a boater wanting to install two 12/24 volt refrigeration systems with BD50 compressors in a large aluminum hull boat. Having seen and experienced the damage cased by low voltage discharge through condenser water I would never again recommend seawater refrigeration cooling on an aluminum boat without adequate electrical isolation and regular sacrificial zinc maintenance. It is one thing to sell a water cooled system that destroys itself but I do not ever again want to be involved with a design that causes a boat hull skin to be reduced to ½ its original thickness in one year because of low voltage discharge. Agree, I shudder when a client suggests condenser cooling via raw water

The Following questions will help test your beliefs on small pleasure boat marine refrigeration.

1. Air cooled refrigeration units of less than 800 Btu per hour are more efficient than water cooled when seawater temperature is above 80 degree F. or below 65 degrees? True or False Both, could be either, it depends on the ambient.

2. Danfoss recommends and approves the BD model compressor to be water cooled in application engineering data sheets? True or FalseMisleading question. For a start Danfoss stopped making compressors 7 years ago so I assume you mean Secop. They and Danfoss in the past don't refer to either water or air cooling in the data sheets,
They refer to evaporator and condenser temperatures, COP etc. but I have never seen where either has any detriment against how a system is condensed with their compressors.

3. Air cooled refrigeration is five times less expensive to maintain than water cooling? True or false Possibly true if raw water cooling although the 5 times figure is a bit of a stretch! False if you refer to the Ozefridge air/water cooled system that cycles fresh water.

4. Water cooled refrigeration systems provide better controlled over refrigerant pressures True or False. Again a general question but absolutely true of most systems using raw water cooling gadgets. But also false because the Ozefridge air/ water cooled system has total control of condenser temperatures and therefore pressures.

6. Water cooled systems cost more than Air cooled? True or False True, our air water cooled model is Au$113.60 more expensive than our air cooled model of the same capacity

7. Water mixed in refrigerant has caused total system replacement? True or False. True and a big problem where raw water has direct contact with the refrigerant galleries. However this DOESN'T and can't occur with the Ozefridge system and the reason we have our own designed air/ water cooled condenser.

8. Compressor life span is much shorter on water cooled units? True or False True if the condenser using raw water erodes away and contaminates the system but false if using the Ozefridge method because the high side pressure /temperature is controlled (unlike most air only systems) thus preventing extreme head pressure in extreme conditions.

9. Damage from low voltage discharge is greater from water cooled units? True or False True but again only when raw water is used.

10. On water cooled units reliable dependable cooling is compromised? True or False False, a prperly engineered air water cooled system is far more efficient (uses less power, cools quicker) and is easier on the compressor.

11. Average qualified refrigeration mechanic understands and can repair the different water cooled small refrigeration units? True or FalseTrue and if they can't they should get another job!

12. Air cooled units put out an average of 300 Btu of uncomfortable heat per hour inside a boat? True or FalseDepends entirely on the installation.

13. Air cooled units can be relied on to work efficiently for weeks or months without someone onboard as long as electricity is available? True or FalseTrue, as can a properly designed air / water cooled system provided they are both fail-safe protected.

14. Variable speed water pumps can help to improve cooling mediums effect on refrigerant pressures? True or False True

15. Using fresh water tank to reduce performance risks of other types of water cooling heat disposal? Good idea or Bad ideaBrilliant idea, I thought you'd never ask! lol

16. Low voltage discharge sacrificial zincs and their regular maintenance are not required on air cooled units? True or False True and not needed on air /water cooled systems using fresh water

17. When salesperson says it is a high end unit could this be just creative advertising? True or F Having personally (or my companies) built and or installed over 8000 refrigeration systems, I have never used or heard the term 'high end unit' so can't comment!

18. Is Water cooling small BD compressor refrigeration units an advantage or disadvantage?

Again a very general question;
In most cases the answer is NO. We manufacture both an air cooled only unit with twin two speed fans and these and other air only brands will do the job for most installations. We also manufacture a very different air /water cooled system for larger cabinets and for where unit location will restrict heat dissipation by air (such as engine room) or if to be used in high ambient areas like the tropics (Its 43C here today!)

I have a late eighties EZ Kold with air and water cooling. After going through a few water pumps in the early years I got rid of the water cooling. Not sure it helped anyway. The unit is still working. Changed the brains a couple of times but the compressor and the R12 is still going strong. Lately the fan seems to have stopped but the holding plate unit still works. Time to upgrade?

Richard, thanks for all your help on refrigeration issues on this forum.

I have a late eighties EZ Kold with air and water cooling. After going through a few water pumps in the early years I got rid of the water cooling. Not sure it helped anyway. The unit is still working. Changed the brains a couple of times but the compressor and the R12 is still going strong. Lately the fan seems to have stopped but the holding plate unit still works. Time to upgrade?

Richard, thanks for all your help on refrigeration issues on this forum.

Rick, if your compressor is good and system still operative then suggest you stay with it but perhaps try to coax someone competent like John from ColdEh (he is near you) to service it for you. Also suggest that when you replace the fan use one with a higher wattage, and power it via a relay with relay coil connected to the Danfoss 'Fan' terminals, but fan load direct from 12VDC supply. This will prevent a faulty fan from scrambling the brains of your Danfoss electronic driver... the expensive bit!

Captubes and TXVs are two very different ways of controlling refrigerant flow

Cap tube systems are very sensitive to ambient temperatures which translates into condensing temperatures . To control this you see the introduction of water cooling to maintain the proper condensing temperatures.
This is important for the total efficiency of the system in the ever changing temperatures that the typical boat sees daily. Inside a home were the ambient temperatures are controlled this is not an issue.

Also a Cap-tube system is limited to the size of the condenser it can use as the system must maintain a balance , more like a chain on two sprockets one must move with the other . TXV systems can use massive condensers . They have a large receiver filter drier to hold the refrigerant for when the TXV calls for it . They work completely differently.

A TXV based system does not care what temperature the condensed refrigerant is at just as long as it is liquid .

Both these systems are totally stable with no lose of efficiency as high as 120F ambient temperature.

WITH NO WATER COOLING

Both these systems are typically more expensive then your captube systems due to the cost of there components, unless you add the cost of a keel cooler to your Captube system and the cost of installing it .

I guess I shouldn't get discouraged and sure this is a pretty technical issue, but 2018 is Technautics 50th Year of being in business making marine refrigeration systems using TXVs and there still are the " it can't true, you lie, it's snake oil" folks out there. If I wasn't moving to La Paz, Mexico next Tuesday it just may bother me a bit more...but I'll soon be serenaded by the sounds of the Taco Carts rather than the Doubters of TXV advantages over Craptubes.....

I guess I shouldn't get discouraged and sure this is a pretty technical issue, but 2018 is Technautics 50th Year of being in business making marine refrigeration systems using TXVs and there still are the " it can't true, you lie, it's snake oil" folks out there. If I wasn't moving to La Paz, Mexico next Tuesday it just may bother me a bit more...but I'll soon be serenaded by the sounds of the Taco Carts rather than the Doubters of TXV advantages over Craptubes.....

I guess I shouldn't get discouraged and sure this is a pretty technical issue, but 2018 is Technautics 50th Year of being in business making marine refrigeration systems using TXVs and there still are the " it can't true, you lie, it's snake oil" folks out there. If I wasn't moving to La Paz, Mexico next Tuesday it just may bother me a bit more...but I'll soon be serenaded by the sounds of the Taco Carts rather than the Doubters of TXV advantages over Craptubes.....

Taco carts? We don't eat at any stinkin taco carts. Try the pop-up sushi restaurant on the Abasolo in the Arjona parking lot most evenings for an interesting La Paz experience.